scholarly journals Evaluation of the courtship and of the hybrid male sterility among Drosophila buzzatii cluster species (Diptera, Drosophilidae)

2002 ◽  
Vol 62 (4a) ◽  
pp. 601-608 ◽  
Author(s):  
L. P. de B. MACHADO ◽  
J. P.de CASTRO ◽  
L. MADI-RAVAZZI
Keyword(s):  
Reproductive Isolation ◽  
Male Sterility ◽  
F1 Hybrids ◽  
Interspecific Crosses ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Drosophila Buzzatii ◽  
Repleta Group ◽  
Reproductive Isolation Mechanisms ◽  
Isolation Mechanisms

In the Drosophila repleta group the establishment of subgroups and complexes made on the basis of morphological and cytological evidences is supported by tests of reproductive isolation. Among species in the repleta group, the buzzatii cluster, due to its polymorphism and polytipism, is an excellent material for ecological and speciation studies. Some interspecific crosses involving Drosophila seriema, Drosophila sp. B, D. koepferae and D. buzzatii strains were completely sterile while others involving strains from these species produced F1 hybrids that did not yield F2. In the present work, data on courtship duration and copula occurrence obtained in the analysis of flies from parental sterile crosses and on spermatozoon mobility observed in F1 hybrids that did not yield F2 are presented. Copula did not occur during one hour of observation and the spermatozoon also did not show mobility at any of the analyzed stages (3, 7, 9 and 10 days old). There was a high variation in courtship average duration and in the percentage of males that courted the females. The reproductive isolation mechanisms indicated by these observations were pre and post-zygotic, as supported by the absence of copula and male sterility. Data obtained also showed the occurrence of different degrees of reproductive compatibility among the strains classified as the same species but from distinct geographic localities.

scholarly journals Extensive introgression despite Haldane’s rule: insights from grasshopper hybrid zones

2021 ◽  
Author(s):  
Linda Hagberg ◽  
Enrique Celemin ◽  
Iker Irisarri ◽  
Oliver Hawlitschek ◽  
J L Bella ◽  
...  
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Male Sterility ◽  
Secondary Contact ◽  
Hybrid Zones ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Haldane’S Rule ◽  
Haldane's Rule ◽  
Species Formation

Although the process of species formation is notoriously idiosyncratic, the observation of pervasive patterns of reproductive isolation across species pairs suggests that generalities, or “rules”, underlie species formation in all animals. Haldane’s rule states that whenever a sex is absent, rare or sterile in a cross between two taxa, that sex is usually the heterogametic sex. Yet, understanding how Haldane’s rule first evolves and whether it is associated to genome wide barriers to gene flow remains a challenging task because this rule is usually studied in highly divergent taxa that no longer hybridize in nature. Here, we address these questions using the meadow grasshopper Pseudochorthippus parallelus where populations that readily hybridize in two natural hybrid zones show hybrid male sterility in laboratorial crosses. Using mitochondrial data, we infer that such populations have diverged some 100,000 years ago, surviving multiple glacial periods in isolated Pleistocenic refugia. Nuclear data shows that secondary contact has led to extensive introgression throughout the species range, including between populations showing hybrid male sterility. We find repeatable patterns of genomic differentiation across the two hybrid zones, yet such patterns are consistent with shared genomic constraints across taxa rather than their role in reproductive isolation. Together, our results suggest that Haldane’s rule can evolve relatively quickly within species, particularly when associated to strong demographic changes. At such early stages of species formation, hybrid male sterility still permits extensive gene flow, allowing future studies to identify genomic regions associated with reproductive barriers.

scholarly journals Age and genetic background determine hybrid male sterility in house mice

2018 ◽  
Author(s):  
Samuel J. Widmayer ◽  
David L. Aylor
Keyword(s):  
Reproductive Isolation ◽  
Male Sterility ◽  
Genetic Factors ◽  
Inbred Strains ◽  
House Mice ◽  
Reproductive Barriers ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Unique Type ◽  
Age Dependent

AbstractHybrid male sterility (HMS) is a unique type of reproductive isolation commonly observed between house mouse (Mus musculus) subspecies in the wild and in laboratory crosses. We identified hybrids that display three distinct trajectories of fertility despite having identical genotypes at the major HMS gene Prdm9 and the X Chromosome. In each case, we crossed female PWK/PhJ mice representative of the M.m.musculus subspecies to males from classical inbred strains representative of M.m.domesticus: 129S1/SvImJ, A/J, C57BL/6J, and DBA/2J. PWK129S1 males are always sterile, while PWKDBA2 males escape HMS. In addition, we observe age-dependent sterility in PWKB6 and PWKAJ males. These males are fertile between 15 and 35 weeks with moderate penetrance. These results point to multiple segregating HMS modifier alleles, some of which have an age-dependent mode of action. Age-dependent mechanisms could have broad implications for the maintenance of reproductive barriers in nature.Author SummaryTwo subspecies of house mice show partial reproductive barriers in nature, and may be in the process of speciation. We used mice derived from each subspecies to replicate hybrid male sterility (HMS) in laboratory mice. Two major genetic factors are well established as playing a role in mouse HMS, but the number of additional factors and their mechanisms are unknown. We characterized reproductive trait variation in a set of hybrid male mice that were specifically designed to eliminate the effects of known genetic factors. We discovered that age played an important role in fertility of some hybrids. These hybrid males showed a delayed onset of fertility, then became fertile for only a few weeks. Across all hybrids males in our study, we observed three distinct trajectories of fertility: complete fertility, complete sterility, and age-dependent fertility. These results point to two or more critical HMS variants with large enough effects to completely restore fertility. This study advances our understanding of the genetic architecture and biological mechanisms of reproductive isolation in mice.

scholarly journals Premeiotic and meiotic failures lead to hybrid male sterility in the Anopheles gambiae complex

2018 ◽  
Author(s):  
Jiangtao Liang ◽  
Igor V. Sharakhov
Keyword(s):  
Anopheles Gambiae ◽  
Male Sterility ◽  
Reproductive Organs ◽  
Mitotic Division ◽  
F1 Hybrids ◽  
Germline Stem Cells ◽  
Hybrid Male ◽  
Strong Suppression ◽  
Hybrid Male Sterility ◽  
Pure Species

AbstractHybrid male sterility contributes to speciation by restricting gene flow between related taxa. Detailed cytological characterizations of reproductive organs in hybrid males is important for identifying phenotypes that can help guide searches of speciation genes. To investigate possible cellular causes of hybrid male sterility, we performed crosses between closely related species of the Anopheles gambiae complex: An. merus with An. gambiae or An. coluzzii. We demonstrate that hybrid male sterility in African malaria mosquitoes involves two defects in the reciprocal crosses: a premeiotic arrest of germline stem cells in degenerate testes and a failure of the reductional meiotic division of primary spermatocytes in normal-like testes. The premeiotic arrest in degenerate testes of hybrids is accompanied by a strong suppression of meiotic and postmeiotic genes. Unlike pure species, sex chromosomes in normal-like testes of F1 hybrids are largely unpaired during meiotic prophase I and all chromosomes show various degrees of insufficient condensation. Instead of entering reductional division in meiosis I, primary spermatocytes prematurely undergo an equational mitotic division producing nonmotile diploid sperm. Thus, our study identified cytogenetic errors in interspecies hybrids that arise during the early stages of postzygotic isolation.

scholarly journals The Genetic Basis of Postzygotic Reproductive Isolation Between Drosophila santomea and D. yakuba Due to Hybrid Male Sterility

Genetics ◽  
2006 ◽  
Vol 173 (1) ◽  
pp. 225-233 ◽  
Author(s):  
Amanda J. Moehring ◽  
Ana Llopart ◽  
Susannah Elwyn ◽  
Jerry A. Coyne ◽  
Trudy F. C. Mackay
Keyword(s):  
Reproductive Isolation ◽  
Male Sterility ◽  
Genetic Basis ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Postzygotic Reproductive Isolation

scholarly journals Genetic Architecture of Autosome-Mediated Hybrid Male Sterility in Drosophila

Genetics ◽  
1996 ◽  
Vol 142 (4) ◽  
pp. 1169-1180
Author(s):  
Ignacio Marín
Keyword(s):  
Male Sterility ◽  
Genetic Architecture ◽  
Relative Size ◽  
Drosophila Species ◽  
Hybrid Male ◽  
Hybrid Male Sterility ◽  
Reciprocal Crosses ◽  
Drosophila Buzzatii ◽  
Number Of Factors ◽  
Two Factors

Abstract Several estimators have been developed for assesing the number of sterility factors in a chromosome based on the sizes of fertile and sterile introgressed fragments. Assuming that two factors are required for producing sterility, simulations show that one of these, twice the inverse of the relative size of the largest fertile fragment, provides good average approximations when as few as five fertile fragments are analyzed. The estimators have been used for deducing the number of factors from previous data on several pairs of species. A particular result contrasts with the authors' interpretations: instead of the high number of sterility factors suggested, only a few per autosome are estimated in both reciprocal crosses involving Drosophila buzzatii and D. koepferae. It has been possible to map these factors, between three and six per chromosome, in the autosomes 3 and 4 of these species. Out of 203 introgressions of different fragments or combinations of fragments, the outcome of at least 192 is explained by the mapped zones. These results suggest that autosome-mediated sterility in the male hybrids of these species is mediated by a few epistatic factors, similarly to X-mediated sterility in the hybrids of other Drosophila species.

scholarly journals Premeiotic and meiotic failures lead to hybrid male sterility in the Anopheles gambiae complex

2019 ◽  
Vol 286 (1906) ◽  
pp. 20191080 ◽  
Author(s):  
Jiangtao Liang ◽  
Igor V. Sharakhov
Keyword(s):  
Anopheles Gambiae ◽  
Male Sterility ◽  
Reproductive Organs ◽  
Mitotic Division ◽  
F1 Hybrids ◽  
Germline Stem Cells ◽  
Hybrid Male ◽  
Strong Suppression ◽  
Hybrid Male Sterility ◽  
Pure Species

Hybrid male sterility (HMS) contributes to speciation by restricting gene flow between related taxa. Detailed cytological characterization of reproductive organs in hybrid males is important for identifying phenotypes that can help guide searches of speciation genes. To investigate possible cellular causes of HMS, we performed crosses between closely related species of the Anopheles gambiae complex: An. merus with An. gambiae or An. coluzzii . We demonstrate that HMS in African malaria mosquitoes involves two defects in the reciprocal crosses: a premeiotic arrest of germline stem cells in degenerate testes and a failure of the reductional meiotic division of primary spermatocytes in normal-like testes. The premeiotic arrest in degenerate testes of hybrids is accompanied by a strong suppression of meiotic and postmeiotic genes. Unlike pure species, sex chromosomes in normal-like testes of F1 hybrids are largely unpaired during meiotic prophase I and all chromosomes show various degrees of insufficient condensation. Instead of entering reductional division in meiosis I, primary spermatocytes prematurely undergo an equational mitotic division producing non-motile diploid sperm. Thus, our study identified cytogenetic errors in interspecies hybrids that arise during the early stages of postzygotic isolation.

scholarly journals The Genetics of Reproductive Isolation in the Drosophila simulans Clade: X vs. Autosomal Effects and Male vs. Female Effects

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1243-1255 ◽  
Author(s):  
Hope Hollocher ◽  
Chug-I Wu
Keyword(s):  
Reproductive Isolation ◽  
Male Sterility ◽  
X Chromosome ◽  
Hybrid Sterility ◽  
Drosophila Simulans ◽  
Female Sterility ◽  
Hybrid Male ◽  
Hybrid Female ◽  
Hybrid Male Sterility ◽  
Hybrid Inviability

Abstract A strong effect of homozygous autosomal regions on reproductive isolation was found for crosses between the species in the Drosophila simulans clade. Second chromosome regions were introgressed from D. mauritiana and D. sechellia into D. simulans and tested for their homozygous effects on hybrid male and hybrid female sterility and inviability. Most introgressions are fertile as heterozygotes, yet produce sterile male offspring when made homozygous. The density of homozygous autosomal factors contributing to hybrid male sterility is comparable to the density of X chromosome factors for this level of resolution. Female sterility was also revealed, yet the disparity between male and female levels of sterility was great, with male sterility being up to 23 times greater than female sterility. Complete hybrid inviability was also associated with some regions of the second chromosome, yet there were no strong sex differences. In conclusion, we find no evidence to support a strong X chromosome bias in the evolution of hybrid sterility or inviability but do find a very strong sex bias in the evolution of hybrid sterility. In light of these findings, we reevaluate the current models proposed to explain the genetic pattern of reproductive isolation.

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